An overview about distributed base station architectures—also known as Cloud Radio Access Network or Centralized Radio Access Network (C-RAN) architectures—as addressed by the present invention is given in “C-RAN—The Road Towards Green RAN”, China Mobile Research Institute, White Paper, Version 2.5, October 2011. Possible C-RAN architecture options currently being considered are as shown in FIGS. 1 and 2, generally referred to by reference numeral 1. Basically, in C-RAN architecture, a functional split is realized between distributed access points and a centralized access controller. More specifically, the access points, according to conventional prior art terminology also referred as radio function units or remote radio heads (RRH) 2, are separated from the access controller/base station 3, also referred as digital function unit or baseband unit (BBU), with a fiber link 4a, 4b between RRHs 2 and access controller/base station 3. The advent of centralized-RAN technology enables the potential to have distributed processing of data.
Currently considered architectures either assume an ideal backhaul 4a (FIG. 1) or near-ideal backhaul 4b (FIG. 2) with delays less than 3 ms in order to support the strict delay requirements for LTE-A (Long Term Evolution—Advanced) systems. Here in both cases, it is assumed that the entities above Layer 2 of the protocol stack (i.e. above the data link layer) would be present at the access controller which, as illustrated in FIGS. 1 and 2, is typically implemented in form of a cloud data center 5 hosting a pool of virtual base stations 3. Depending on the backhaul conditions, either fully or partially centralized RAN infrastructure could be deployed.